When it comes to diagnosing Zika virus infection in newborns, the eyes may have it.
Researchers from the Fernandes Figueira-Fundação Oswaldo Cruz
in Rio de Janeiro, which has assumed a leadership role in multiple avenues of study regarding the mosquito-borne virus, believe that eye abnormalities such as an impaired optic nerve and/or retina as well as unilateral microophthalmia may hold the key in effective early identification of the disease in infants. They identified these potential diagnostic markers based on their analysis of scores of infants with confirmed Zika virus infection; the results
of which were published on July 17, 2017 in JAMA Ophthalmology.
“The take-home message of our study is that that eye abnormalities may be the only initial finding in congenital Zika virus,” study coauthor Andrea A. Zin, MD, PhD, an ophthalmologist at Fundação Oswaldo Cruz, told Contagion®
. “We believe that all infants with potential Zika virus exposure should undergo screening eye examinations.”
For their research, Dr. Zin and her colleagues enrolled 230 infants with prenatal microcephaly—a hallmark symptom of Zika—and/or other symptoms, or who had mothers who tested positive for the mosquito-borne virus during pregnancy. In the end, they excluded 118 of the infants, either because they didn’t test positive for Zika via RT-PCR, or because they were found to have other genetic abnormalities that explained their symptoms.
Of the 112 infants included in the analysis, all of whom had confirmed Zika virus infection via RT-PCR, only 20 had microcephaly, and 31 had other CNS abnormalities (such as ventriculomegaly, cerebral calcifications, posterior fossa abnormalities, pachygyria, and lissencephaly). The authors performed eye exams on 78 of the study participants at least once and 36 at least twice; 8 study participants underwent 3 exams.
Dr. Zin and her colleagues identified sight-threatening eye abnormalities in 14 of 20 infants with microcephaly, and 2 of the 31 infants with other CNS symptoms. Among the 61 infants without microcephaly at birth, 8 had eye abnormalities with impaired optic nerve and/or retina, the most common finding (n=19). Of those with optic nerve abnormalities, 18 had them in both eyes; 11 of the infants with optic nerve damage had bilateral optic nerve atrophy, and 7 had optic nerve hypoplasia (6 bilateral); 1 study participant had bilateral coloboma.
Even among those infants without optic nerve damage, 4 presented with bilateral pigment mottling or retinal hemorrhages (3 infants). In all, 15 infants had focal pigment mottling, chorioretinal atrophy, hemorrhages, and/or bilateral inferior coloboma. In addition, nystagmus was found in 6 of 24 infants with eye abnormalities; 4 of these patients also had microcephaly. None of the 24 infants had clinical signs of active anterior or posterior uveitis, the authors note.
Dr. Zin and her colleagues—a team that includes pediatricians, neurologists, physiotherapists, and occupational therapists—plan to follow the infants enrolled in the study for an as-yet indeterminate period, with exams every 3 months to track their overall neurodevelopment. They believe there is much to learn from all of the infants included in the analysis, even those without apparently healthy eyes. However, in the short-term, they believe their findings are sufficient to warrant the inclusion of routine eye exams for infants born to mothers with confirmed Zika virus infections in guidelines for the diagnosis and management of the disease in mothers and newborns.
Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.
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